Trigger lockout and kickback mechanism for surgical instruments

ABSTRACT

A forceps includes an end effector assembly including first and second jaw members, a blade, a lever member operably coupled to the end effector, a trigger member operably coupled to the blade and defining an actuation path therealong. A trigger safety member is pivotably coupled to the lever member such that, when the lever member is disposed in an initial position, the trigger safety member is disposed in a position blocking the trigger member. When the lever member is disposed in a compressed position, the trigger safety member is disposed in a position, wherein the trigger safety member is displaced from the actuation path to permit movement of the trigger member, wherein the safety member rotates relative to the lever member as a function of movement of the lever member to block/unblock the trigger member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 14/814,602, filed on Jul. 31, 2015, which is a continuation of U.S. patent application Ser. No. 13/401,964, filed Feb. 22, 2012, now U.S. Pat. No. 9,113,940, which is a continuation-in-part of U.S. patent application Ser. No. 13/006,538, filed Jan. 14, 2011, now U.S. Pat. No. 8,945,175, the entire contents of each of which is incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to surgical instruments. More particularly, the present disclosure relates to a trigger lockout and kickback mechanism for use with surgical instruments.

Background of Related Art

Electrosurgical instruments, e.g., forceps, utilize both mechanical clamping action and electrical energy to effect hemostasis by heating tissue and blood vessels to coagulate, cauterize and/or seal tissue. As an alternative to open forceps for use with open surgical procedures, many modern surgeons use endoscopic or laparoscopic instruments for remotely accessing organs through smaller, puncture-like incisions or natural orifices. As a direct result thereof, patients tend to benefit from less scarring and reduced healing time.

Many endoscopic surgical procedures require cutting or ligating blood vessels or vascular tissue. Due to the inherent spatial considerations of the surgical cavity, surgeons often have difficulty suturing vessels or performing other traditional methods of controlling bleeding, e.g., clamping and/or tying-off transected blood vessels. By utilizing an endoscopic electrosurgical forceps, a surgeon can either cauterize, coagulate/desiccate and/or simply reduce or slow bleeding simply by controlling the intensity, frequency and duration of the electrosurgical energy applied through the jaw members to the tissue. Most small blood vessels, i.e., in the range below two millimeters in diameter, can often be closed using standard electrosurgical instruments and techniques. However, if a larger vessel is ligated, it may be necessary for the surgeon to convert the endoscopic procedure into an open-surgical procedure and thereby abandon the benefits of endoscopic surgery. Alternatively, the surgeon can seal the larger vessel or tissue. Typically, after a vessel or tissue is sealed, the surgeon advances a knife to sever the sealed tissue disposed between the opposing jaw members.

SUMMARY

As used herein, the term “distal” refers to the portion that is being described which is further from a user, while the term “proximal” refers to the portion that is being described which is closer to a user.

In accordance with at least one aspect of the present disclosure, a forceps includes an end effector assembly including first and second jaw members, at least one of the jaw members movable relative to the other between an open position and a closed position for grasping tissue therebetween. The forceps further includes a blade movable between a retracted position wherein the blade is proximal to the jaw members and a deployed position wherein the blade extends at least partially between the jaw members to cut tissue grasped therebetween, a lever member movable between an initial position and a compressed position to move the jaw members between the open and closed positions, and a trigger member operably coupled to the blade and positionable to move the blade between the retracted position and the deployed position, the trigger member defining an actuation path therealong. The forceps also include a trigger safety member pivotably coupled to the lever member such that, when the lever member is disposed in the initial position, the trigger safety member is disposed in a position, blocking actuation of the trigger member and when the lever member is disposed in the compressed position, the trigger safety member is disposed in a position wherein the trigger safety member is displaced from the actuation path to permit movement of the trigger member, wherein the safety member rotates relative to the lever member as a function of movement of the lever member to block/unblock the trigger member.

In accordance with another aspect of the present disclosure, the forceps further include a housing enclosing at least a portion of the lever member, the trigger member, and the trigger safety member.

In accordance with yet another aspect of the present disclosure, the lever member is operably coupled to the housing at a pivot and the trigger member is operably coupled to the housing at a different pivot.

In accordance with yet another aspect of the present disclosure, the lever member and the trigger member are operably coupled to the housing at a single pivot.

In accordance with another aspect of the present disclosure, the forceps further include at least one blade deployment member operably coupled to the blade at an engagement pin and to the trigger member about a pivot.

In accordance with another aspect of the present disclosure, the forceps further include a drive assembly operably coupled to at least one of the first and second jaw members and positionable to actuate the jaw members between the open position and the closed position.

In accordance with another aspect of the present disclosure, the forceps further include at least one driving member operably coupled to the housing, to the trigger safety member, and to the drive assembly at a driving end.

In accordance with yet another aspect of the present disclosure, the lever member is operably coupled to trigger safety member about a trigger pivot.

In accordance with another aspect of the present disclosure, the forceps further include a latch mechanism configured to releasably secure the lever member in the compressed position.

In accordance with yet another aspect of the present disclosure, the trigger safety member is further configured to kickback and forcibly return the trigger member to an un-actuated position.

In accordance with another aspect of the present disclosure, the forceps further include a spring to bias the trigger member towards an un-actuated position.

In accordance with another aspect of the present disclosure, a forceps include a housing and an end effector assembly including first and second jaw members, at least one of the jaw members movable relative to the other between an open position and a closed position for grasping tissue there between. The forceps further have a blade, the blade movable between a retracted position wherein the blade is proximal to the jaw members and a deployed position wherein the blade extends at least partially between the jaw members to cut tissue grasped therebetween, and a lever member coupled to the housing and to the end effector assembly and movable between an initial position and a compressed position to move the jaw members between the open position and the closed position. The forceps further have a trigger member operably coupled to the housing and coupled to the blade via a blade deployment member, wherein the blade deployment member is operably coupled to the blade at an engagement pin, wherein the trigger member is positionable to move the blade between the retracted position and the deployed position, the trigger member defining an actuation path therealong, a drive assembly operably coupled to at least one of the first and second jaw members to actuate the jaw members between the open position and the closed position, and at least one driving member operably coupled to the housing at a point, to the trigger safety member a different point, and to the drive assembly at a driving end. The forceps also have a trigger safety member pivotably coupled to the lever member such that, when the lever member is disposed in the initial position, the trigger safety member is disposed in a position blocking actuation of the trigger member, and when the lever member is disposed in the compressed position, the trigger safety member is disposed in a position wherein the trigger safety member is displaced from the actuation path to permit movement of the trigger member, wherein the safety member rotates relative to the lever member as a function of movement of the lever member to block/unblock the trigger member.

In accordance with another aspect of the present disclosure, the forceps further include a latch mechanism configured to releasably secure the lever member in the compressed position.

In accordance with another aspect of the present disclosure, the trigger safety member is further configured to kickback and forcibly return the trigger member to an un-actuated position.

In accordance with another aspect of the present disclosure, the forceps further include a spring to bias the trigger member towards an un-actuated position.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the present disclosure are described herein with reference to the drawings, wherein like reference numerals identify similar or identical elements:

FIG. 1A is a perspective view of a forceps including an end effector assembly in accordance with an aspect of the present disclosure wherein jaw members of the end effector assembly are disposed in a spaced-apart position;

FIG. 1B is a perspective view of the forceps of FIG. 1A wherein the jaw members of the end effector assembly are disposed in an approximated position;

FIG. 2 is a perspective view of a handle assembly of the forceps of FIG. 1A wherein a portion of the housing has been removed to show the internal components therein, the handle assembly including a latch mechanism disposed in an initial position;

FIG. 3 is a perspective view of the handle assembly of the forceps of FIG. 1A wherein a portion of the housing has been removed to show the internal components therein and wherein the latch mechanism is disposed in an actuated position;

FIG. 4 is an isolated, perspective view of a lever of the latch mechanism of FIGS. 2 and 3 ;

FIG. 5 is an isolated, perspective view of a pin track member and cantilever spring of the latch mechanism of FIGS. 2 and 3 ;

FIG. 6 is a schematic illustration of the use of the latch mechanism of FIGS. 2 and 3 ;

FIG. 7 is a perspective view of the handle assembly of the forceps of FIG. 1A wherein a portion of the housing has been removed to show the internal components therein, the handle assembly including another aspect of a latch mechanism disposed in an actuated position;

FIG. 8 is a isolated, perspective view of a pin track member and cantilever spring of the latch mechanism of FIG. 7 ;

FIG. 9 is an isolated, perspective view of a lever of the latch mechanism of FIG. 7 ;

FIG. 10 is a transverse, cross-sectional view of the lever of FIG. 9 ;

FIG. 11 is a schematic illustration of the use of the latch mechanism of FIG. 7 ;

FIG. 12 is a perspective view of a blade in accordance with an aspect of the present disclosure and configured for use with the forceps of FIG. 1A;

FIG. 13 is a perspective view of a shaft and a portion of an end effector assembly configured for use with the forceps of FIG. 1A;

FIG. 14A is a cross-sectional view of the end effector assembly of FIG. 13 in an open position with the blade in a retracted position;

FIG. 14B is a cross-sectional view of the end effector assembly of FIG. 13 in a closed position with the blade in the retracted position;

FIG. 14C is a cross-sectional view of the end effector assembly of FIG. 13 in a closed position with the blade in a deployed position;

FIG. 15A is a side view of a handle and trigger assembly provided in accordance with an aspect of the present disclosure, wherein the lever member is in an initial position and the trigger is locked-out;

FIG. 15B is a side view of the handle and trigger assembly of FIG. 15A where the lever member is in a transitional state between the initial position and a compressed position;

FIG. 15C is a side view of the handle and trigger assembly of FIG. 15A, wherein the lever member is in the compressed position and the trigger is unlocked; and

FIG. 15D is a side view of the handle and trigger assembly of FIG. 15A, wherein the lever is in the compressed position and the trigger has been activated.

DETAILED DESCRIPTION

Turning now to FIGS. 1A and 1B, forceps 10 is one example of an instrument for use in accordance with the present disclosure. Forceps 10 including a housing 20, a handle assembly 30, a lever latch assembly 40, a trigger assembly 80, a rotating assembly 85, and an end effector assembly 100. Forceps 10 further includes a shaft 12 having a distal end 14 configured to mechanically engage end effector assembly 100 and a proximal end 16 that mechanically engages housing 20. Alternatively, any surgical instrument having a lever latch assembly operable to control one or more functions of the end effector assembly may be provided.

With continued reference to FIGS. 1A and 1B, end effector assembly 100 includes a pair of opposing jaw members 110 and 120. End effector assembly 100 is designed as a unilateral assembly, i.e., jaw member 120 is fixed relative to the shaft 12 and jaw member 110 is moveable about a pivot 103 relative to jaw member 120. However, either, or both jaw members 110, 120 may be moveable with respect to the other. In either embodiment, jaw members 110, 120 are moveable from a spaced-apart position, as shown in FIG. 1A, to an approximated position, as shown in FIG. 1B, to grasp tissue therebetween. Further, one or both of jaw members 110, 120 may include an electrically conductive tissue sealing surface 112, 122, respectively. Sealing surfaces 112, 122 are disposed in opposed relation relative to one another such that, with jaw members 110, 120 in the approximated position grasping tissue therebetween, electrosurgical energy may be supplied to one or both of sealing surfaces 112, 122 of jaw members 110, 120, respectively, to seal tissue grasped therebetween.

One or both of jaw members 110, 120 may also include a longitudinally extending blade channel 130 to permit reciprocation of a blade (not shown) therethrough for dividing tissue grasped therebetween. Trigger assembly 80 is operably coupled to the blade (not shown) such that, upon actuation of trigger 82, the blade (not shown) is translated from a retracted position to an extended position wherein the blade (not shown) is advanced between jaw members 110, 120 to cut tissue grasped therebetween. Further, trigger 82 may be biased toward an un-actuated position such that, upon release of trigger 82, the blade (not shown) is returned to the retracted position.

Rotating assembly 85 is integrally associated with housing 20 and is rotatable in either direction about a longitudinal axis “X-X” to rotate jaw members 110, 120 with respect to housing 20 about longitudinal axis “X-X.”

Handle assembly 30 extends downwardly from housing 20 and is releasably engageable with housing 20. Handle assembly 30 is ergonomically configured such that, when engaged with housing 20, a surgeon may grasp handle assembly 30 and operate lever latch assembly 40, trigger assembly 80 and/or rotating assembly 85 with a single hand. Handle assembly 30 further includes a battery pack (not shown) disposed within a battery housing 32. The battery pack (not shown) of handle assembly 30 provides power to forceps 10, e.g., for energizing sealing surfaces 112, 122 of jaw members 110, 120, respectively. More particularly, the battery pack (not shown) is configured to electrically couple to a generator (not shown) disposed within housing 20 for powering the generator (not shown). The generator (not shown), in turn, supplies the desired energy to sealing surfaces 112, 122 of jaw members 110, 120, respectively, of end effector assembly 100. Alternatively, forceps 10 may be configured to be coupled to an external power source (not shown) and/or generator (not shown), e.g., via an electrosurgical cable (not shown).

With reference to FIGS. 2 and 3 , in conjunction with FIGS. 1A and 1B, battery housing 32 of handle assembly 30 includes mechanical keying features (not shown) configured complementarily to the mechanical keying features associated with housing 20 such that handle assembly 30 may be securely locked in mechanical engagement with housing 20. The battery pack (not shown) is electrically coupled to the generator (not shown), and may also be released from housing 20, e.g., to replace or recharge the battery pack (not shown).

Continuing with reference to FIGS. 2 and 3 , one embodiment of a lever latch assembly 40 is shown including a lever 41 pivotably coupled to housing 20 and extending downwardly therefrom. Lever 41 is ultimately connected to drive assembly 90 that, together, mechanically cooperate to impart movement of jaw members 110 and 120 between the spaced-apart position (FIG. 1A) and the approximated position (FIG. 1B). As mentioned above, spatial constraints within housing 20 limit the positioning of lever 41, e.g., such that the generator (not explicitly shown) and other control circuitry (not explicitly shown) may be disposed above drive assembly 90 within housing 20. Further, as will become apparent below, the working components of lever latch assembly 40 are all relatively closely-spaced with respect to one another, thereby providing more area within housing 20 for the generator (not shown) and for engagement of the battery pack (not shown).

Continuing with reference to FIGS. 2 and 3 , lever 41 is selectively moveable from an initial position (FIG. 2 ), wherein lever 41 is spaced-apart from handle assembly 30, to an actuated position (FIG. 3 ), wherein lever 41 is positioned adjacent to handle assembly 30, to move jaw members 110, 120 from the spaced-apart position (see FIG. 1A) to the approximated position (see FIG. 1B). As will be described below, lever latch assembly 40 is configured to permit movement of lever 41 between the initial position (FIG. 2 ) and the actuated position (FIG. 3 ) and for releasably locking lever 41 in the actuated position. Accordingly, lever latch assembly 40 is configured to selectively move jaw members 110, 120 (FIGS. 1A and 1B) between the spaced-apart position and the approximated position and to releasably lock jaw members 110, 120 (FIGS. 1A and 1B) in the approximated position. Further, lever 41 may be biased toward the initial position (FIG. 2 ), such that jaw members 110, 120 are biased toward the spaced-apart position (FIG. 1A).

Turning now to FIG. 4 , in conjunction with FIGS. 2-3 , lever 41 of lever latch assembly 40 includes a proximally-extending tab 43. Tab 43 extends at least partially into housing 20, e.g., through a slot (not shown) defined therein. More particularly, a proximal tip 44 of tab 43 extends into housing 20 when lever 41 is disposed in the initial position (FIG. 2 ), while the entire tab 43 (or a substantial portion thereof) extends into housing 20 when lever 41 is moved to the actuated position (FIG. 3 ). Tab 43 extends into housing 20 above handle assembly 30, as best shown in FIGS. 2 and 3 , such that, when the battery pack (not shown) is engaged to housing 20, tab 43 may still be advanced into housing 20 upon movement of lever 41 from the initial position (FIG. 2 ) to the actuated position (FIG. 3 ).

A pin 45 is integrally formed with, or fixedly engaged to tab 43 of lever 41 and extends proximally therefrom. Pin 45 may be formed from a metal or other rigid material. As tab 43 is advanced into housing 20 upon movement of lever 41 from the initial position to the actuated position, pin 45 is similarly advanced into housing 20 toward pin track member 46 (FIG. 5 ). In other words pin 45 is translated along an arc upon movement of lever 41 between the initial position and the actuated position. However, since pin 45 is fixedly engaged within lever 41 and since lever 41 is pivotably engaged to housing 20, the transverse position of pin 45 relative to housing 20 is fixed. More specifically, pin 45 is transversely aligned with a neutral axis “N-N” (FIG. 6 ) defined by cantilever spring 47 throughout movement of lever 41 between the initial position and the actuated position.

As best shown in FIG. 5 , pin track member 46 defines a track 50 configured to permit translation of pin 45 therealong. Pin track member 46 is engaged, or integrally formed, e.g., insert molded, with a cantilever spring 47 at a first end 48 of cantilever spring 47. Cantilever spring 47 is coupled at a second end 49 thereof to housing 20, e.g., via protrusion-aperture friction fitting, or other suitable engagement. In other words, cantilever spring 47 is fixedly coupled to housing 20 at second end 49 thereof, while first end 48 of cantilever spring 47, having pin track member 46 disposed thereon, is free. At-rest, cantilever spring 47 is biased toward an aligned position defining the neutral axis “N-N” (FIG. 6 ). However, cantilever spring 47 is capable of being flexed off of the neutral axis “N-N” (FIG. 6 ) in both a positive direction “+” (FIG. 6 ) and a negative direction “−” (FIG. 6 ). As such, upon urging of pin track member 46 and, thus, the free first end 48 of cantilever spring 47 in either direction relative to the fixed second end 49 of cantilever spring 47, cantilever spring 47 is flexed off of the neutral axis “N-N” (FIG. 6 ) such that pin track member 46 is repositioned relative to the neutral axis “N-N” (FIG. 6 ). Under the bias of cantilever spring 47 toward an aligned position with respect to the neutral axis “N-N” (FIG. 6 ), pin track member 46 is likewise biased toward an aligned position with respect to the neutral axis “N-N” (FIG. 6 ).

Turning now to FIG. 6 , in conjunction with FIGS. 2-3 , the operation of lever latch assembly 40 will be described. Initially, with lever 41 disposed in the initial position (and, thus, with jaw members 110, 120 disposed in the spaced-apart position (FIG. 1A)), pin 45 extends minimally into housing 20, spaced-apart from pin track member 46. As shown in FIG. 6 , this position corresponds to position P₁. When it is desired to close jaw members 110, 120 (FIG. 1A), e.g., for grasping tissue therebetween, the surgeon grasps handle assembly 30 and lever 41 and pulls lever 41 proximally toward handle assembly 30, i.e., toward the actuated position. As lever 41 is moved from the initial position toward the actuated position, drive assembly 90 imparts movement of jaw members 110, 120 from the spaced-apart position to the approximated position. At the same time, as lever 41 is pulled proximally, tab 43 is advanced proximally into housing 20 such that pin 45 is translated, in transverse alignment with neutral axis “N-N,” toward pin track member 46 to position P₂. However, at this point, pin track member 46 remains aligned on the neutral axis “N-N” under the bias of cantilever spring 47.

Upon further movement of lever 41 toward the actuated position, pin 45 is advanced further proximally into housing 20, eventually contacting an outer surface 51 of pin track member 46. With pin 45 transversely fixed with respect to the neutral axis “N-N,” pin 45 causes cantilever spring 47 to be flexed and urges pin track member 46 off of the neutral axis “N-N” in a negative direction “−” as pin 45 is translated through position P₃. More specifically, the outer surface 51 of pin track member 46 is angled relative to neutral axis “N-N” such that, as lever 41 is pulled further toward the actuated position, pin 45 is slid proximally along outer surface 51 of pin track member 46, urging pin track member 46 off of the neutral axis “N-N.”

Once lever 41 has been moved to the actuated position, corresponding to the approximated position of jaw members 110, 120 (FIG. 1B), respectively, of end effector assembly 100, pin 45 has been slid proximally past angled outer surface 51 of pin track member 46 to a position P₄ adjacent first end 53 of track channel 52 of pin track member 46. In this position P₄, with pin 45 no longer contacting outer surface 51 of pin track member 46, pin 45 no longer urges pin track member 46 off of the neutral axis “N-N.” As such, cantilever spring 47 is flexed back toward the aligned position, thereby moving pin track member 46 back toward alignment with the neutral axis “N-N.”

When the actuated position of lever 41 has been achieved, such that jaw members 110, 120 (FIG. 1B) are disposed in the approximated position to grasp tissue therebetween, lever 41 is automatically locked in the actuated position to fix jaw members 110, 120 (FIG. 1B) in the approximated position. More particularly, once pin 45 is positioned adjacent first end 53 of track channel 52, cantilever spring 47 biases pin track member 46 back toward the neutral axis “N-N” such that pin 45 is translated along track channel 52 from position P₄ at the first end 53 of track channel 52 to position P₅ at the saddle portion 54 of track channel 52. Even if lever 41 is released at this point, pin 45 is retained in position within saddle portion 54 of track channel 52 of pin track member 46. Specifically, pin track member 46 inhibits distal translation of pin 45 and, thus lever 41, thereby maintaining jaw members 110, 120 (FIG. 1B) in the approximated position. Further, with pin 45 disposed in position P₅, i.e., with pin 45 disposed within saddle portion 54 of track channel 52 of pin track member 46, pin track member 46 is inhibited from returned into alignment with neutral axis “N-N.”

Pin track member 46 may include one or more feedback features (not shown) for providing tactile and/or audible feedback notifying the surgeon that lever 41 has been translated to the actuated position. For example, saddle portion 54 may be configured to provide an audible or tactile response when pin 45 is translated into saddle portion 54, e.g., when pin 45 is moved to position P₅. Such a feature indicates to the surgeon that lever latch assembly 40 is in the locked position and that lever 41 may be released to lock jaw members 110, 120 in the approximated position.

With lever latch assembly 40 maintaining lever 41 in the actuated position and, thus, maintaining jaw members 110, 120 (FIG. 1B) in the approximated position with tissue grasped therebetween, electrosurgical energy may be supplied to sealing surfaces 112, 122 of jaw members 110, 120, respectively, to effect a tissue seal (see FIG. 1B). Thereafter, trigger 82 may be actuated to advance the blade (not shown) between jaw members 110, 120 to cut tissue along the previously formed tissue seal. Finally, lever latch assembly 40 may be unlatched, as described in further detail below, allowing lever 41 to return to the initial position and allowing jaw members 110, 120 (FIGS. 1A and 1B) to return to the spaced-apart position to release tissue such that forceps 10 may be removed from the surgical site.

In order to unlock lever latch assembly 40, lever 41 is moved further proximally from the actuated position a sufficient distance to dislodge pin 45 from saddle portion 54 of track channel 52 of pin track member 46. In other words, lever 41 is moved proximally such that pin 45 is no longer retained within saddle portion 54. Track channel 52 is configured such that, once pin 45 is removed from saddle portion 54, pin 45 enters open second end 55 of track channel 52. Once pin 45 is moved into the open second end 55 of track channel 52, e.g., once pin 45 is moved to position P₆, pin 45 no longer inhibits pin track member 46 from returning under the bias of cantilever spring 47 to the aligned position with respect to neutral axis “N-N.” As such, cantilever spring 47 is returned to the at-rest position, thereby returning pin track member 46 into alignment with neutral axis “N-N.”

At this point, with pin 45 in position P₆, the surgeon may release lever 41. Similarly as discussed above, pin track member 46 may include feedback features (not shown) for providing a tactile or audible indication to the surgeon that pin 45 has been removed from saddle portion 54 of track channel 52 and, thus, that lever 41 may be released allowing jaw members 110, 120 (FIGS. 1A and 1B) to return to the spaced-apart position.

Upon release of lever 41 by the surgeon, lever 41 is returned back to the initial position. As such, pin 45 is translated distally relative to pin track member 46 and housing 20. More particularly, pin 45 is translated distally from position P₆ along inner surface 56 of pin track member 46. Inner surface 56 of pin track member 46 is angled such that, as pin 45 is translated therealong to position P₇, cantilever spring 47 is flexed to permit pin track member 46 to be repositioned off of the neutral axis “N-N” in a positive direction “+.” Upon further distal translation of pin 45 to position P₈, pin 45 exits second end 55 of track channel 52 of pin track member 46, allowing pin track member 46 to return under the bias of cantilever spring 47 back into alignment with the neutral axis “N-N.” Thereafter, lever is further returned, e.g., under the bias, back to the initial position corresponding to position P₁ of pin 45 and corresponding to the spaced-apart position of jaw members 110, 120 of end effector assembly 100 (FIGS. 1A and 1B).

Turning now to FIGS. 7-9 , another embodiment of a lever latch assembly 60 is shown configured for use with a surgical instrument, e.g., forceps 10. Similar to lever latch assembly 40 discussed above (see FIGS. 2-6 ), lever latch assembly 60 includes a lever 61 pivotably coupled to housing 20 and extending downwardly therefrom. Lever 61 is ultimately connected to drive assembly 90 that, together, mechanically cooperate to impart movement of jaw members 110 and 120 between the spaced-apart position (FIG. 1A) and the approximated position (FIG. 1B). More particularly, lever 61 is selectively moveable from an initial position, wherein lever 61 is spaced-apart from handle assembly 30, to an actuated position, wherein lever 61 is positioned adjacent to handle assembly 30, to move jaw members 110, 120 from the spaced-apart position (see FIG. 1A) to the approximated position (see FIG. 1B).

With continued reference to FIGS. 7-9 , lever latch assembly 60 is similar to lever latch assembly 40 in that lever latch assembly 60 is configured to permit movement of lever 61 between the initial position and the actuated position and for releasably locking lever 61 in the actuated position. Accordingly, lever latch assembly 60 is configured to selectively move jaw members 110, 120 between the spaced-apart position (FIG. 1A) and the approximated position (FIG. 1B) and to releasably lock jaw members 110, 120 in the approximated position (FIG. 1B). Further, lever 61 may be biased toward the initial position, such that jaw members 110, 120 are biased toward the spaced-apart position (FIG. 1A).

As best shown in FIG. 9 , lever 61 of lever latch assembly 60 includes a pair of flanges 63 extending upwardly therefrom. Flanges 63 extend into housing 20 to couple lever 61 to housing 20. A crossbar 64 extends between flanges 63 in a generally perpendicular orientation with respect to flanges 63. A cantilever spring 65 is fixedly engaged at a first end 67 thereof to crossbar 64 and includes a pin 66 integrally formed with, or otherwise engaged to free second end 68 of cantilever spring 65. Cantilever spring 65 extends downwardly and proximally from crossbar 64 of flanges 63 of lever 61 such that pin 66 extends generally toward housing 20. More specifically, when lever 61 is disposed in the initial position, pin 66 is spaced-apart from housing 20. On the other hand, when lever 61 is moved to the actuated position, pin 66 is positioned adjacent housing 20. Further, cantilever spring 65 is positioned off-center on crossbar 64, i.e., cantilever spring 65 is positioned asymmetrically between flanges 63 of lever 61. At-rest, cantilever spring 65 is biased toward an aligned position defining the neutral axis “N-N” (FIGS. 10 and 11 ). However, cantilever spring 65, similar to cantilever spring 65, is capable of being flexed off of the neutral axis “N-N” (FIGS. 10 and 11 ) in both a position direction “+” and a negative direction “−” to thereby reposition pin 66 off of the neutral axis “N-N” (FIGS. 10 and 11 ).

Referring to FIGS. 7-11 , lever latch assembly 60 also includes a pin track member 69 defining a track 70 configured to permit translation of pin 66 therealong. Pin track member 69 is engaged to, or integrally formed with housing 20 in a generally distal-facing orientation and is positioned to at least partially intersect the neutral axis “N-N.” As such, upon movement of lever 61 from the initial position to the actuated position, pin 66 is translated along an arc toward housing 20 and, thus, toward pin track member 69, eventually engaging pin track member 69. As will be described in greater detail below, with pin track member 69 fixedly engaged to housing 20, and with pin 66 engaged to lever 61 via cantilever spring 65, movement of lever 61 between the initial position and the actuated position causes pin track member 69 to urge the free second end 68 of cantilever spring 65 off of the neutral axis “N-N” such that pin 66 is repositioned relative to the neutral axis “N-N” to releasably lock lever 61 in the actuated position.

The operation of lever latch assembly 60 will now be described. Initially, with lever 61 disposed in the initial position (and, thus, with jaw members 110, 120 disposed in the spaced-apart position (FIG. 1A)), pin 66 is spaced-apart from pin track member 69 and, thus, cantilever spring 65 is aligned on neutral axis “N-N.” As shown in FIG. 6 , this position corresponds to position P₁′. When it is desired to close jaw members 110, 120 (FIGS. 1A-1B), e.g., for grasping tissue therebetween, the surgeon grasps handle assembly 30 and lever 61 and pulls lever 61 proximally toward handle assembly 30, i.e., toward the actuated position. As lever 61 is moved from the initial position toward the actuated position, drive assembly 90 imparts movement of jaw members 110, 120 from the spaced-apart position to the approximated position (FIG. 1B). At the same time, as lever 61 is pulled proximally, pin 66 is advanced proximally toward housing 20 such that pin 66 is translated toward pin track member 69, represented by position P₂′. However, at this point, pin 66 is still spaced from pin track member 69 and, thus, remains aligned on the neutral axis “N-N” under the bias of cantilever spring 65.

Upon further movement of lever 61 toward the actuated position, pin 66 is advanced further proximally toward housing 20, eventually contacting an outer surface 71 of pin track member 69. Due to the angled configuration of outer surface 71 of pin track member 69 relative to the neutral axis “N-N,” and with pin track member 69 transversely fixed with respect to the neutral axis “N-N,” cantilever spring 65 is flexed and pin 66 is urged of the neutral axis “N-N” in a negative direction “−” as pin 66 is translated through position P₃′ and along outer surface 71.

Once lever 61 has been moved to the actuated position, corresponding to the approximated position of jaw members 110, 120, respectively, of end effector assembly 100 (FIGS. 1A and 1B), pin 66 has been slid proximally past angled outer surface 71 of pin track member 69 to a position P₄′ adjacent first end 72 of track channel 74 of pin track member 69. In this position P₄′, with pin 66 no longer contacting outer surface 71 of pin track member 69, pin track member 69 no longer urges pin 66 off of the neutral axis “N-N.” As such, cantilever spring 65 is flexed back toward the aligned position, thereby moving pin 66 back toward alignment with the neutral axis “N-N.”

When lever is moved to the actuated position and is subsequently released, lever latch assembly 60 releasably locks lever 61 in the actuated position to fix jaw members 110, 120 in the approximated position (see FIG. 1B). More particularly, once pin 66 is positioned adjacent first end 72 of track channel 74, cantilever spring 65 biases pin 66 back toward the neutral axis “N-N” such that pin 66 is translated along track channel 74 from position P₄′ at the first end 72 of track channel 74 to position P₅′ at the saddle portion 75 of track channel 74. In this position, pin track member 69 inhibits distal translation of pin 66 and, thus lever 61, thereby maintaining jaw members 110, 120 in the approximated position. As in the previous embodiment, pin 66 and/or pin track member 69 may include one or more feedback features (not shown) for providing tactile and/or audible feedback notifying the surgeon that lever 61 has been translated to the actuated position.

With lever latch assembly 60 maintaining lever 61 in the actuated position and, thus, maintaining jaw members 110, 120 (FIG. 1B) in the approximated position with tissue grasped therebetween, electrosurgical energy may be supplied to sealing surfaces 112, 122 of jaw members 110, 120, respectively, to effect a tissue seal (see FIG. 1B). Thereafter, trigger 82 may be actuated to advance the blade (not shown) between jaw members 110, 120 (FIG. 1B) to cut tissue along the previously formed tissue seal. Finally, lever latch assembly 60 may be unlatched, as will be described in greater detail below, allowing lever 61 to return to the initial position and allowing jaw members 110, 120 (FIGS. 1A and 1B) to return to the spaced-apart position to release tissue such that forceps 10 may be removed from the surgical site.

In order to unlock lever latch assembly 60, lever 61 is moved further proximally from the actuated position a sufficient distance to dislodge pin 66 from saddle portion 75 of track channel 74 of pin track member 69. In other words, lever 61 is moved proximally such that pin 66 is no longer retained within saddle portion 75. Track channel 74 is configured such that, once pin 66 is removed from saddle portion 75, pin 66 enters open second end 73 of track channel 74. Once pin 66 is moved into the open second end 73 of track channel 74, e.g., once pin 66 is moved to position P₆′, pin track member 69 no longer inhibits pin 66 from returning under the bias of cantilever spring 65 to the aligned position with respect to neutral axis “N-N.” As such, cantilever spring 65 is returned to the at-rest position, thereby returning pin 66 into alignment with neutral axis “N-N.” At this point, with pin 66 in position P₆′, the surgeon may release lever 61, allowing jaw members 110, 120 to return to the spaced-apart position (see FIG. 1A). Upon release of lever 61 by the surgeon, lever 61 is returned back to the initial position. As such, pin 66 is translated distally relative to pin track member 69 and housing 20. More particularly, pin 66 is translated distally from position P₆′ along inner surface 76 of pin track member 69. Inner surface 76 of pin track member 69 is angled such that, as pin 66 is translated therealong to position P₇′, cantilever spring 65 is flexed to permit pin 66 to be repositioned off of the neutral axis “N-N” in a positive direction “+.” Upon further distal translation of pin 66 to position P₈′, pin 66 exits second end 73 of track channel 74 of pin track member 69, allowing pin 66 to return under the bias of cantilever spring 65 back into alignment with the neutral axis “N-N.” Thereafter, lever 61 is further returned, e.g., under the bias, back to the initial position corresponding to position P₁′ of pin 66 and corresponding to the spaced-apart position of jaw members 110, 120 of end effector assembly 100 (FIG. 1A).

Referring to FIGS. 12-14C, a blade 1200 configured for use with forceps 10 (FIG. 1A), or any other suitable surgical instrument, generally includes a blade 1201 engaged to a blade shaft 1203 having at least one pin hole 1205 defined therein. Blade 1200 is configured for slidable translation within shaft 1307 (similar to shaft 12 of forceps 10 (FIG. 1A)) such that blade 1200 may slide through and relative to shaft 1307 between a retracted position and a deployed position, wherein blade 1201 extends at least partially between jaw members 1310, 1320 of end effector assembly 1301 (similar to end effector assembly 100 of forceps 10 (FIG. 1A)).

Referring to FIGS. 14A, 14B and 14C, shaft 1307 and end effector assembly 1301 are shown incorporating blade 1200 therein. In FIG. 14A, jaw members 1310, 1320 are disposed in an open position and blade 1201 is disposed in a retracted position. In FIG. 14B, jaw members 1310, 1320 are disposed in a closed position, while blade 1201 remains disposed in the retracted position. In FIG. 14C, jaw members 1310, 1320 are in the closed position and the blade 1201 has been deployed to extend at least partially between jaw members 1310, 1320.

Turning now to FIGS. 15A, 15B, 15C, and 15D, in conjunction with FIGS. 12, 13 and 14A-14C, a handle and trigger assembly 1500 is shown configured to operate blade 1200 and end effector assembly 1301. Handle and trigger assembly 1500 includes a trigger member 1502 that is pivotably coupled to the housing of the instrument (e.g., housing 20 of forceps 10 (FIG. 1A)) at a first pivot 1505. The trigger member 1502 is operably coupled to a blade deployment member 1510 at a second pivot 1511. More specifically, second pivot 1511 couples trigger member 1502 to blade deployment member 1510 at one end of blade deployment member 1510, while engagement pin 1513 couples the other end of blade deployment member 1510 to blade shaft 1203 of blade 1200 via engagement of engagement pin 1513 through a slot 1305 defined within shaft 1307 and into engagement with pinhole 1205 defined within blade shaft 1203. The slot 1305 defined within shaft 1307 allows translation of engagement pin 1513 so that blade 1200 easily transitions within shaft 1200, e.g., between the retracted and deployed positions (FIGS. 14B and 14C, respectively). Any of the pivots may be any functional mechanical interface suitable for the desired purpose including, but not limited, to a rotatable connection, a slidable connection, a cam-follower, etc.

In operation, as the trigger member 1502 is pulled proximally, from an un-actuated position towards an actuated position, trigger member 1502 is pivoted about first pivot 1505 and blade deployment assembly member 1510 is translated distally such that engagement pin 1513, which, as mentioned above, is engaged to blade shaft 1203 of blade 1200 via pin hole 1205, is slid along slot 1305 allowing the blade 1200 to slidably move within shaft 1307, ultimately to deploy blade 1201 between jaw members 1310, 1320 of end effector assembly 1301, e.g., to move blade 1201 between the retracted and deployed positions (FIGS. 14B and 14C, respectively). Movement of the trigger member 1502 about first pivot 1505 in the other direction, e.g., back towards the un-actuated position, retracts blade 1200. A spring 1550 disposed about shaft 1307 may function to bias trigger member 1502 distally, such that, upon release of trigger member 1502, trigger member 1502 is returned distally to the un-actuated position such that blade 1201 is returned to the retracted position.

Handle and trigger assembly 1500 further includes a lever member 1544, at least a portion of which is disposed inside the housing of the instrument (e.g., housing 20 of forceps 10 (FIG. 1A)) and operably coupled to the housing via a third pivot. In an embodiment, pivot 1505 functions as both the first and third pivots, e.g., the pivot 1505 for both lever member 1544 and trigger member 1502 as is shown in FIGS. 15A-15D. Lever member 1544 is configured to move between a first or initial position and a second or compressed position to open and close jaw members 1310, 1320 of end effector assembly 1301 in a similar manner as described above with respect to lever 40 and jaw members 110, 120 (see FIGS. 1A-11 ).

Handle and trigger assembly 1500 further includes driving member 1501 operably coupled to a drive assembly 1590 at a driving end 1507. The driving member 1501 may be operably connected to the housing (not shown) via at a point, e.g. a fourth pivot 1508. Driving member 1501 is coupled to end effector assembly 1301 via drive assembly 1590 such that movement of driving member 1501 effects longitudinal translation of drive assembly 1590 which, in turn, effects movement of jaw members 1310, 1320 of end effector assembly 1301 between the open and closed positions. Driving end 1507 of driving member 1501 may be operably connected to drive assembly 1590 via engagement of driving end 1507 within mandrel 1592 of drive assembly 1590. Other suitable connections may also be used.

Driving member 1501 is coupled to lever member 1544 such that, upon movement of lever member 1544 from the initial position to the compressed position, driving member 1501 is pivoted about fourth pivot 1508 to urge drive assembly 1590 to translate proximally, thereby moving jaw members 1310, 1320 of end effector assembly 1301 from the open position to the closed position to grasp tissue therebetween. Moving lever member 1544 from the compressed position back to the initial position returns jaw members 1310, 1320 of end effector assembly 1301 to the open position. A spring 1560 disposed about drive assembly 1590 may function to bias drive assembly 1590 distally such that, upon release of lever member 1544, lever member 1544 is returned to the initial position and jaw members 1310, 1320 are returned to the open position.

Handle and trigger assembly 1500 further includes a trigger safety member 1503 that is operably coupled between lever member 1544, trigger member 1502, and driving member 1501. More specifically, trigger safety member 1503 is coupled to lever member 1544 via a fifth or trigger pivot 1506 and to driving member 1501 at a different point, e.g. via a sixth pivot 1504. Trigger safety member 1503 includes a first portion 1503 a extending distally from fifth pivot 1506 and a second portion 1503 b extending proximally from fifth pivot 1506 and coupled to driving member 1501 via sixth pivot 1504.

When the lever member 1544 is in the initial position, as shown in FIG. 15A, in conjunction with FIGS. 12, 13 and 14A-14C, trigger safety member 1503 is oriented such that first portion 1503 a of safety member 1503 blocks, or prevents trigger member 1502 from being actuated. More specifically, first portion 1503 a of safety member 1503 intercepts the path of trigger member 1502 below first pivot 1505 to prevent pivoting of trigger member 1502 to deploy blade 1201. This position of safety member 1503 corresponds to a locked state of handle and trigger assembly 1500. As can be appreciated, in this locked state, safety member 1503 inhibits deployment of blade 1201 when the lever 1544 is not being compressed. Generally, when the lever 1544 is uncompressed, the jaw members 1310, 1320 are disposed in the open position, and when the lever 1544 is compressed, the jaw members 1310, 1320 are in the closed position. However, the jaw members 1310, 1320 may be held in a substantially open position by thick tissue even when the lever 1544 is compressed, in which case the blade 1201 may still be deployed as the safety member 1503 is rotated out of the path of the trigger member 1502 due to the position of the lever 1544.

As shown in FIG. 15B, in conjunction with FIGS. 12, 13 and 14A-14C, as lever 1544 is moved from the initial position towards the compressed position to close jaw members 1310, 1320, safety member 1503 begins to rotate about pivot 1506 out of the path of trigger member 1502 so as to no longer block, or inhibit deployment of blade 1201. The position of the lever 1544 that is required to allow safety member 1503 to no longer block the trigger member 1502 may be selectable as a design feature as desired. For example, the safety member 1503 may block the trigger member 1502 until the lever 1544 is completely compressed. Alternatively, the safety member 1503 may allow the trigger member 1502 to be operated when the lever is at any desired position between the initial position and the compressed position.

Turning to FIG. 15C, in conjunction with FIGS. 12, 13 and 14A-14C, once lever member 1544 reaches the compressed position, trigger safety member 1503 has already rotated out of the path of trigger member 1502 such that trigger member 1502 may be actuated by the user, e.g., rotated proximally about pivot 1505, to deploy blade 1201 between jaw members 1310, 1320 to cut tissue grasped therebetween. More specifically, as shown in FIG. 15C, with lever member 1544 in the compressed position, first portion 1503 a of safety member 1503 no longer intercepts the path of trigger member 1502, but, rather, is rotated such that first portion 1503 a is disposed above pivot 1505, no longer interfering with the range of motion of trigger member 1502. This position of safety member 1503 corresponds to an unlocked state of handle and trigger assembly 1500.

Turning to FIG. 15D, in conjunction with FIGS. 12, 13 and 14A-14C, with lever member 1544 in the compressed position, and, thus, with handle and trigger assembly 1500 is in the unlocked state, trigger member 1502 may be actuated to deploy blade 1201 between jaw members 1310, 1320 of end effector assembly 1301 to cut tissue grasped therebetween.

Handle and trigger assembly 1500 may further include a latch mechanism 1546, similar to any of the latch mechanisms described above (see FIGS. 1-11 ), or any other suitable latch mechanism. Latch mechanism 1546 is configured to releasably retain lever member 1544 in the compressed position, thereby maintaining jaw members 1310, 1320 in the closed position.

Upon unlatching lever member 1544 from latch mechanism 1546 and returning lever member 1544 towards the initial position (or, simply upon return of lever member 1544, in instances where latching is not provided or used), safety member 1503 is rotated and translated back towards the locked state. Such a feature is particularly useful in situations where trigger member 1502 is stuck in the deployed position, e.g., where trigger member 1502 does not return under bias of spring 1550 after being released. More specifically, as safety member 1503 is rotated and translated back towards the locked state, first portion 1503 a contacts trigger member 1502 (if trigger member 1502 has not already been returned under bias to the initial position) and urges trigger member 1502 back towards its initial position, thereby returning blade 1201 to the retracted position. In other words, not only does safety member 1503 provide a “safety lockout” that inhibits deployment of blade 1201 when jaw members 1310, 1320 are in the open position, but safety member 1503 also provides a “kickback” feature that returns blade 1201 to the retracted position as jaw members 1310, 1320 are returned to the open position.

From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

What is claimed:
 1. A surgical instrument, comprising: a housing; a handle extending downwardly from the housing; a shaft extending distally from the housing; an end effector assembly disposed at a distal end of the shaft, the end effector assembly including first and second jaw members, at least one of the first or second jaw members movable relative to the other between a spaced-apart position and an approximated position; a lever pivotably coupled to the housing via a first pivot, the lever including a tab extending into the housing and a lever handle extending out from the housing to permit manual manipulation thereof; a drive assembly extending from the housing through the shaft to operably couple to the at least one of the first or second jaw members, the drive assembly operably coupled to the lever such that pivoting the lever relative to the housing from a first position to a second position translates the drive assembly through the housing and the shaft to thereby move the at least one of the first or second jaw members relative to the other from the spaced-apart position to the approximated position; and a latch assembly configured to releasably secure the lever in the second position, the latch assembly including a pin extending from the tab of the lever and a pin track disposed within the housing, the pin positioned outside of the pin track when the lever is in the first position and the pin positioned inside of the pin track when the lever is in the second position, the pin configured to travel through the pin track along a first path to lock the latch assembly and along a second path to unlock the latch assembly.
 2. The surgical instrument according to claim 1, wherein the drive assembly defines a longitudinal axis and wherein the first pivot is located below the longitudinal axis.
 3. The surgical instrument according to claim 1, further comprising a spring disposed about the drive assembly and configured to bias the drive assembly distally, thereby biasing the at least one of the first or second jaw members towards the spaced-apart position.
 4. The surgical instrument according to claim 1, further comprising: a blade operably coupled to the end effector assembly and movable relative thereto between a retracted position and a deployed position; and a trigger pivotably coupled to the housing and extending from the housing to permit manual manipulation thereof, the trigger operably coupled to the blade and movable along an actuation path to move the blade between the retracted position and the deployed position.
 5. The surgical instrument according to claim 4, further comprising: a trigger safety member directly coupled to the lever and configured such that, when the lever is disposed in the first position, the trigger safety member is disposed in the actuation path to block actuation of the trigger, and when the lever is disposed in the second position, the trigger safety member is displaced from the actuation path to permit actuation of the trigger.
 6. The surgical instrument of claim 5, wherein, when the lever is returned from the second position to the first position, the trigger safety member forcibly urges the trigger along the actuation path back towards an un-actuated position.
 7. The surgical instrument of claim 5, wherein a driving link operably couples the lever and the driving assembly, the driving link is pivotably coupled to the housing via a second pivot spaced-apart from the first pivot and the trigger is pivotably coupled to the housing via a third pivot different from the first and second pivots.
 8. The surgical instrument according to claim 7, wherein the drive assembly defines a longitudinal axis and wherein the first, second, and third pivots are located below the longitudinal axis.
 9. The surgical instrument of claim 7, wherein the trigger safety member is directly coupled to the driving link.
 10. The surgical instrument of claim 9, wherein the trigger safety member is pivotably coupled to the lever via a fourth pivot and to the driving link via a fifth pivot.
 11. The surgical instrument of claim 4, wherein the trigger is pivotably coupled to the housing via the first pivot.
 12. The surgical instrument of claim 1, wherein the latch assembly further includes a cantilever spring coupling the pin with the lever or coupling the pin track with the housing.
 13. The surgical instrument of claim 1, wherein the pin is formed with or fixedly engaged to the tab of the lever and extends proximally therefrom.
 14. The surgical instrument of claim 1, wherein the handle is releasably engaged with the housing.
 15. The surgical instrument of claim 14, wherein the handle defines a battery housing therein.
 16. A surgical instrument, comprising: a housing; a handle extending downwardly from the housing; a shaft extending distally from the housing; an end effector assembly disposed at a distal end of the shaft, the end effector assembly including first and second jaw members, at least one of the first or second jaw members movable relative to the other between a spaced-apart position and an approximated position; a blade operably coupled to the end effector assembly and movable relative thereto between a retracted position and a deployed position; a lever pivotably coupled to the housing via a first pivot, the lever including a tab extending into the housing and a lever handle extending out from the housing to permit manual manipulation thereof; a drive assembly extending from the housing through the shaft to operably couple to the at least one of the first or second jaw members, the drive assembly operably coupled to the lever by a driving link, the driving link pivotably coupled to the housing via a second pivot spaced-apart from the first pivot such that pivoting the lever relative to the housing from a first position to a second position translates the drive assembly through the housing and the shaft to thereby move the at least one of the first or second jaw members relative to the other from the spaced-apart position to the approximated position; a trigger pivotably coupled to the housing via a third pivot different from the first and second pivots, the trigger extending from the housing to permit manual manipulation thereof, the trigger operably coupled to the blade and movable along an actuation path to move the blade between the retracted position and the deployed position; a latch assembly configured to releasably secure the lever in the second position, the latch assembly including a pin extending from the tab of the lever and a pin track disposed within the housing, the pin configured to travel through the pin track along a first path to lock the latch assembly and along a second path to unlock the latch assembly; and a trigger safety member directly coupled to the lever and configured such that, when the lever is disposed in the first position, the trigger safety member is disposed in the actuation path to block actuation of the trigger, and when the lever is disposed in the second position, the trigger safety member is displaced from the actuation path to permit actuation of the trigger.
 17. The surgical instrument of claim 16, wherein, when the lever is returned from the second position to the first position, the trigger safety member forcibly urges the trigger along the actuation path back towards an un-actuated position.
 18. The surgical instrument of claim 16, wherein the trigger is pivotably coupled to the housing via the first pivot.
 19. The surgical instrument of claim 16, wherein the trigger safety member is directly coupled to the driving link.
 20. The surgical instrument of claim 19, wherein the trigger safety member is pivotably coupled to the lever via a fourth pivot and to the driving link via a fifth pivot. 